Orthopedic insole



Dec. 30, 1952 D. J. MoRToN 2,623,307

ORTHOPEDIC INSOLE Filed June 14, 1950 2 SHEETS- SHEET 1 INVENTOR. DUDLEYJ. MORTON ATTORNEYS Dec. 30, 1952 Q 1 MQRTQN 2,523,307

ORTHOPEDIC INSOLE Filed June 14, 1950 2 SHEETS-SHEET 2 INVENTOR. DUDLEYJ.' MORTON ATTORNEYS Patented Dec. 30, 1952 UNITED STATES PATENT OFFICEORTHOPEDIC INSOLE Dudley J. Morton, New York, N. Y.

Application June 14, 1950, Serial No. 168,090

` 3 Claims.

This invention relates to a method and apparatus for treating footl andarch disorders in human feet. l

In the accompanying'drawings':

4Figure l is a view 'of a normal human foot showing the weight load onthe metatarsal bones;

Figure 2 isa view of a human foot where deficient support by metatarsalI through shortness or looseness, identifies the distorted weightdistribution. The abnormal overload on metatarsal II and III is thebasic factor in causing progressive deformity in bone structure andpainful damage to the soft tissuesas herein described;

Figure 3 is a view of a vhuman foot as shown in Figure 2 but with theinstant method applied so as to correct the abnormal condition andrestore the weight distribution to that shown in Figure 1;

Figure 4 is a view looking down upon a left insole constituting anapparatus suitable for practicing the herein disclosed method;

Figure 5 is a bottom view of the insole Figure 4; Y

Figure 6 is an edge view of the insole, Figure 4 with the partsseparated to show their relative position before being secured together;and

Figures 7 to 10 inclusive, are sectional views on the lines 1 to l0inclusive, Figure 4.

In order to properly understand the following disclosure of the methodand a preferred form of apparatus for practicing the same, briefreference will be made to some fundamental facts respecting the humanfoot, which must be understood before this method can be applied to thecorrection of foot and arch disclosures.

The framework of the human foot (composed of the combination of solidbone segments with the effective cohesion of the ligaments which bindthem together), is the 'means ywhereby weight stresses are sustained andtransmitted from the ankle to the pointsof contact of that frameworkwith the ground; namely, the heel in back and the front ends of themetatarsal bones in front. Thus, the bones of the feet have the mostintimate and primary working relationship with the force of gravity inthe interaction between foot structure and that external force. vWithouttheir bony framework, the feet would tbe useless as weight-supportingand locomotive organs.

This primary relationship has been only vaguelly recognized andcompletely overlooked in the prevailing concepts of foot function and of-disfordered function.

Primary importance is wrongly ascribed to the muscles and to weakness ofthe muscles, and often foot specialists fail to understand that thefoots bony framework is comp-arable to the chassis of an automobile forthe support of gravitational stresses either when stationary or inaction; While the muscles are comparable with the motor whose kineticpower is concerned only in moving the load borne by the chassis.

With bodyweight (gravity) recognized as the only mechanical force,habitually operating upon the foots framework and of magnitude capableof damaging action, it is essential that the division of bodyweight beknown from the points of reception (ankle) to each of the points ofweight-bearing contact with the ground; namely, the heel in back, `andin frontthe front ends of the ve metatarsal bones. Measurement of thedownward force by instruments designed for this purpose gave twodistinct patterns of weight distribution as characteristic of normalfunction (1) in standing and (2) in locomotion. With total bodyweightreckoned as 24 equal units (for example, in a lb. individual each unitwould be l2242=5 pounds) the distribution in standing would be asfollows: 12 units (60` lbs.) would be transmitted down each leg to theankle. From there, 6 units (30 lbs.) is transmitted to the point of heelcontact; the other 6 units (30 lbs.) are transmitted by the metatarsalbones subdivided so that 2 units (10 lbs.) is borne by metatarsal I, and1 unit (5 lbs.) is borne by each of the other four metatarsal bones.

These measurements demonstrate ye facts of fundamental importance.

1.Each metatarsal bone has normal weightbearing contact with the ground.i

2. The fallacy of the traditional concept of a transverse arch as formedby the front ends of the metatarsal bones, with metatarsals I and Vbearing on the ground and the middle ones, II, III and IV, occupying anelevated arched position. That faculty premise is necessary to theerroneous explanation of metatarsal disorder as due to a downwarddisplacement (falling of the alleged metatarsal arch) of the threemiddlebones. f

3. The equal division of the 6 metatarsal units (3 and 3) on each sideof the foots central axis (running between metatarsals II, and III)indicates that the structural stability (balance) of 3 the foot fromside to side is furnished by metatarsal I on the medial side, andmetatarsal V on the lateral side.

4. The major role of metatarsal I becomes apparent because (1) it islocated on the inner border of the foot; (2) and therefore is primarilyfor the support and stability of the foot structure along this elevatedand arched inner border; and (3) it normally carries the greatest shareof bodyweight in the front half of the foot.

5. Hence, its major role makes it the member most disruptive to normalfoot function if or when its ability to supply proper support isimpaired Vor defective.

However, the most conspicuous evidence of the major importance ofmetatarsal I is shown in locomotion during the phase when the entirebodyweight is borne on one foot andthe heel is lifted from the ground inpropelling bodyweight forward. During these moments, the entire load.(24 units) is carried by the metatarsal bones. I-Iere the distributionvfollows a pattern in Which half of the .load ('12 units) is sustainedby metatarsal I and the other half (l2 units) is distributed among the,fourlateral metatarsal'bones. Thus, metatarsal I is called upon tosustain a load as great as 'is required ,of the large ,bones of eitherleg during the act of standing.

Disordered weight-bearing, ,all vdegrees Yof postural instability andunbalance, or ultimate breakdown of the foots arched contour must findits primary source in the defective support by one supporting member.That member .is clearly identified by the character and location ofthesymptoms and signs observed ,in .the ,two most common types of footdisorder. They are commonly spoken of as falling of the (longitudinal)arches, and dropping of the metatarsal arch.

This will lbe -understood by referring to Figure 1 .showing the weightdistribution in ya normal foot. Here the vblack areas indicatemetatarsal load in the ratio of 2l-1-l1. VIt will be observed that, just-as a chair with a loose leg inevitably tilts in the direction of theloose leg, an habitual inward tilt of the foot points directly todeficient support by the supporting bone on the inner border of the footdue to laxity or looseness in its attachment to the main framework.

Also, to demonstrate that it is not caused by muscular weakness, a footthat possesses normal distribution of Weight to all points of groundcontact, maintains a balanced normal `posture under bodyweight evenvthough all the ,leg muscles to the foot are paralyzed.

Deficient support by the loose chair leg inevitably causes exaggerationof weight to'be borne by other legs. When metatarsal I fails to supplyits normal share of support through laxity of its basal joints(intercuneiform and naviculocuneiform), the unsupported share istransposed to metatarsalII, and to a 'lesserdegree to .metatarsal III,as indicated in Figure 2. This habitual transfer of excess weight onmetatarsal vII is demonstrated structurally in a progressive enlargement.or strengthening of the shaft of that bone by an increase in vitsdiameter and/or `thickening of its cortex. Skin callus appear in adultfeet at X under the front end of that bone, and muscle pains resultfrequently from faulty overstrain on .the muscles because of theunbalanced foot posture.

The foregoing condition is illustrated in Figure 2. Here metatarsal I isdefective (although the foot may be well arched and posture good). Theweight, as indicated 'by the black areas, is

4 transposed to metatarsal II and, to a lesser degree, to metatarsalIII.

The second type of disorder is located chieny in the metatarsal region.It occurs predominantly in women in association with the continuous useof high heels. Since all metatarsal bones have direct weight bearingcontact with the ground in normal function, there can be no downwarddisplacement to explain the occurrence of painful symptoms in thisregion. vAlthough the disordered weight distribution of a loosemetatarsal I frequently causes metatarsalgic symptoms, deficiency ofsupport by this bone due to shortness is more specific-ally the directcause of this more localized disorder.

With a short metatarsal I, weight distribution may not be seriouslyaffected when the feet are in a position of normal standing--with heelson the ground. However when the heels are lifted in locomotion andweight is thrown upon the forepart of the supporting foot, the moreadvanced position of the front end of the longer metatarsal II causesthe major share of bodyweight to become increasingly concentrated uponthat boneinstead or" upon the shorter metatarsal I. Enlargingdevelopment of metatarsalII and III are oftenconspicuously seen inX-raypictures of these feet. The prevalence of painful symptoms of this typeof disorder in w-omen is clearly explained when the heels are kept in anelevated position both in standing and locomotion by the use of their.higher shoeh'eels. The skin calluses x, 'Figure 2, under the front endof that bone which is so common `in Women is a striking demonstration ofthe disordered weight distribution upon the metatarsal bones.

Avoidance or correction of the disabling symptoms of foot disordersrequires recognition of these two principal `phases of damaging actionthat results from improper distribution of the bodys weight stressesthrough .the feet. The primary phase pertains to the bones of the feetas the direct medium for the foots action against the force of gravity.The accompanying underloaded segments are lof course, not involved insuch danger.

For illustration.-If of two persons of the saine weight, one had normalweight distribution through the feet, `and in the other, certainsegments of his feet carried an abnormally large share of the load,while other segments carried `less than normal; it would not bediflicult to predict which personwas most likely to develop fooi'ltrouble and just Where in lhis foot structure the liability is located.

The herein disclosed method of establishing freedom from the injury of`disordered function inthis primary 'phase is to eliminate or dissipatefrom the overloading segments the weight stresses which are in excess ofthe normal share of load those par should carry; i. e. by establishingnormal weight distribution.

The secondary phase of damaging action is that which is incurred by thesoft tissues through localized abnormal pressures and faulty distortedand exaggerated strains. Since the nerves are most intimately associatedwith the soft tissues, this lphase includes all the painful symptoms andneurological disturbances that are typical of these disorders. Theabnormal pressures are identied in the excess weight which the front endof the overloaded metatarsals transmit to the small area `of flesh andskin immediately beneath them. This concentration of intensied pressureproduces a traumatic irritation of the tissues and imbedded nerves thatcauses the typical burning sensation of the soles. Under continuedfunction, it causes more rapid proliferation and growth of skin cellswhich results in the formation of localized calluses which become anadded source lof painful symptoms.

Faulty strains are imposed upon the ligaments because of abnormaltransmission of weight stresses through the contact surfaces of thejoints. These strains are caused either by uneven contact of adjacentjoint surfaces through forced disalignment of the bones from faultyposture or by an excess load on such joints. Strains of this sort areidentified by points of localized tender ness in the region of theaffected joint or joints and of their ligaments.

Other strains are the ones imposed upon the muscles. They result: (l)from an unnatural and abnormal load being deected on the muscles becauseof postural unbalance (pronation) of the feet, or (2) from sustainedover-activity of the muscles to protect the feet from pressure upon somepainful weightbearing point such as a painful callus. These strainsproduce the muscular symptoms of early fatigue, aches, and spasms in thefeet and legs.

The two phases of damaging action, on bone and on soft tissues, requiredifferent but desirably coordinated methods of treatment as hereindescribed, to help to counteract the primary causes and symptomaticeffects ici. these common types of foot trouble. Analysis shows thatolecient support in weight bearing by metatarsal I is the directmechanical cause. That deficiency is due to a laxity and/or a shortnessof this ysegment. It can be directly overcome as taught herein, .by theintervention of a piece of solid material I5 between the front end ofthat bone and the ground, of sumcient thickness to eliminate the slackin ligaments when the segment is loose, or to compensate for the neededlength when that segment is short. Just as a suitable block placed undera short leg of a table stabilizes the table and establishes equaldistribution of weight on all four legs, this procedure stabilizes theentire bony framework of the foot and eliminates or modifies thedamaging element of overload by a more normal redistribution of bodyWeight. This is the basic mechanical feature of the compeneating insoleherein described, because it effects foot function at its Very source inbone structure.

Also, by establishing firm supporting contact of metatarsal I with theground, the entire floot structure becomes stabilized, therebycorrecting faulty strains on ligaments and muscles that result frompostural insecurity. (pronation).

The second important feature of the device described herein provides ameans lto counteract the excessive bruising pressure on the soft tissueswhich have been concentrated upon the small areas immediately under thefront ends of the overloaded metatarsal bones. When such pressure pointshave caused painful irritation of these tissues (traumatic) cellulitiswith nerve involvement, and have induced the formation of calluses, itis often insufficient merely to reduce the overload ion these bones toanormal load; because under total bodyweight, even normal degrees ofpressure in these localized irritated areas is too severe for thechronically bruised and inflamed state of these tissues and for thehypersensitive and highly irritable state of the nerves. Even normalpressures will perpetuate the state of cellular irritation and pain. Itis therefore necessary to minimize weight stresses on those 6 localizedpoints that have been subject to the damaging action of concentratedpressure. This is accomplished by diffusing the pressure as widely aspossible over adjacent areas; and the most effective means of doing sodepends upon three yspecifications in its design.

1. The weight-diffusing element must be made of pressure-sustainingmaterial (preferably of moderate resiliency).

2. The tapered front margin of the element must be in immediate relationto the rear margin of the small metatarsal area of ground contact. Thetaper is of an angle to supply counter pressure against the tissuesunder the metatarsal shaft and thereby increase posteriorly the area oftransmitted pressure so that the 'localized intensity of pressurebecomes reduced according to enlargement in the area of transmission.

3. In order to gain greatest reduction of irritating pressure on theirritated spots, the device is extended across the foot. In this mannerweight stresses can be diffused over the largest area and encourage theforepart of the foot to perform its full range of normal weight-bearingfunction.

Now, referring to Figures 4 to 10, inclusive, a compensating insole willbe seen suitable for use in practicing the method herein disclosed.

While a shoe can be constructed to permanently embody in the shoestructure the platform and weight-diffusing elements hereinafterdescribed, the preferred means is to provide an insole having theseelements, as same constitutes an article easy to manufacture and whichcan be applied by the user to any shoes, thereby obviating the necessityof having special shoes made to order.

Referring to Figure 4, the numeral il denotes the upper layer top memberof the insole and is made of leather or the like. It fits into the shoesand extends from the extreme rear point I2 of the heel to a point I3just below the ball of the foot and behind the juncture of the fourmetatarsal bones and their phalanges.

The top I I is formed with a forwardly extended portion I4 which extendsunder the front end of the first metatarsal and forms (together lwithpad I5) a platform to compensate for any shortness or laxness in thismetatarsal and to restore even weight distirbution for the reasonspreviously explained. The total weight is now redistributed from itsfaulty ratio shown in Figure 2, to its normal ratio as shown in Figure3, and therefore conforms to Fig. 1. Thus, one object of the in ventionis attained; to wit, correction of weight distribution due to metatarsaldisorder.

The pad I5 is made of the necessary thickness to suit the foot to whichit is applied, bearing in mind that even weight distribution should beattained, as described in connection with Figure 1. When so applied, thefoot condition is corrected from that shown in Figure 2 to normal,Figure 1.

Referring to Figure 6, the top member I l carrying the pad I5 has astiffening liner Iii of any suitable material such as commonly employedfor such liners cemented or otherwise secured thereto, and same coversthe insole from heel I2 to a point I1, a short distance in front of theupwardly curved instep portion i8 of the insole.

A bottom member I9, preferably of leather, is now attached to the base II and is of exactly the same shape as II. The stitching 2t may passthrough the liner I6 of any desired thickness.

The outer edges of members I9 and II may be cemented together'a-ndtooled to present a closed rounded -edge,-'and the curved instep portionI8 maybeformed in the 'insole by pressing same to the `desired shape.

The entire insole unit may, if desired, be pressed or otherwise shapedto conform generally to the bottom of the foot, provided the pad i5 andmember 2l (hereinaftervdescribed) are so placed as to function as hereindescribed when said insole is so shaped.

The second essential object or this invention, to'counteract theexcessive bruising pressure on the soft tissues immediately under thefront end `of overloaded metatarsal bones, is attained by securing aweight-diiusing element or member 21 to member l by cement or any othersuitable manner.

The element 2l maybe of rather dense sponge rubber or 'the like, but isnot to be considered as aipadfor support, as its real function is todistribute the weight applied `thereto by the four lateral metatarsalsafter same has been corrected as just described over a considerable areaas defined by said member which, as best seen in Figure .5, willunderlie all the metatarsals immediately rearwardly of the contactpoints thereof, andthen extend rearwardly toward the heel a suiiicientdistance to diiuse the weight applied during 'weight-bearing.

`It will tbe observed that the member 2i does not e'xtendto or 'supportthe arch of the foot and does'not come Ynear'the tai-sal bones.

The edges ofthe member 2l may be rounded to `present a neat appearanceand it may be tapered toward the -front and rear edges as shown bydotted lines 22, Figure 6.

Referring to Figure 2, it will be seen that with 'the rst metatarsal inthe condition described, heavy callus appear under the second and third.metatarsals This is due to the abnormal distribution of weight, aspreviously described, and this condition is corrected by applying themember ZI which, together with pad l5, acts to diffuse the weight overthe surface enclosed by dotted lines 23 Ain Figure 3, the second mainobject of this invention being thus attained.

Other objects and advantages of the invention will be apparent from theforegoing, this disclosure being illustrative and not limitative of theinvention. Many modifications can be made by those skilled in the art,and therefore the invention is as dened by the appended claims.

What is claimed is:

1. An insole vadapted to be inserted in a shoe and comprising a memberadapted to underlie a human foot and having a front extension radapted'to extend only under the forward end of the first metatarsal bone ofthe foot, a noncushioning pad secured to said front extension andunderlying the head of the rst metatarsal bone only and adapted tocompensate for shortness or laxity of said first metatarsal, and aweight-diiusing cushion member secured to the bottom of said insole andunderlying the shafts of all the metatarsal bones from a point imediately back of the heads of all the metartarsals 8 and adapted, whenin a shoe, to diu'se pressure vover an area extending behind andtransverse said insole, said weight-diiusing cushion member extendinglaterally across said insole substantially the full width thereof.

2. An insole adapted to be inserted in a shoe, and comprising top andbottom members adapted to underlie a human foot and having a frontextension adapted to extend only under the forward end of the rstmetatarsal bone of said foot, a non-cushioning pad secured between saidfront extension and underlying the head of the iirst metatarsal boneonly and adapted to compensate for shortness or laxity of saidrnetatarsal, means for securing said members together with said padtherebetween, and a weight-diiusing cushion member secured to theunderside of said bottom member and extending transverseiy of same, andunderlying the shafts of all the metatarsal bones from a pointimmediately back of the heads of all the metatarsals and adapted, whenworn in a shoe, to diuse pressure over an area extending behind andtransverse ysaid insole, said weight-diffusing cushion member extendinglaterally across said insole substantially the full width thereof.

3. An insole adapted to be inserted in a shoe and comprising top andbottom members adapted to underlie a human foot inY said shoe, saidmembers having a front extension adapted to extend only under theforward end of the rst metatarsal bone of said foot, a non-cushioningpad secured between said front extension and underlying the head of thefirst metatarsal bone only and adapted to compensate for shortness orlaxity thereof, a stiiening element secured between said members andextending from the heel to a point forward of the instep of said insole,means for securing said members together with said pad and saidstiiening member therebetween, and a weight-dilusing cushion membersecured to said insole and extending transversely of the same andforward of said stiffening member and underlying the shafts o all thenietatarsal bones from a point immediately back of the heads of all saidmetatarsals and adapted, when worn in a shoe, to diffuse weight over theentire area defined by said cushion member, said last member extendinglaterally across insole substantially the full width thereof.

DDLL'Y J. VRTON.

REFERENCES CTED The following references are of record in the le of thispatent:

UNITED STATES PATENTS Number Name Date 1,841,942 Fenton Jan. 19, i9321,847,973 Morton l, 1932 1,849,734: Scholl Mar. 15, 1932 2,148,999 Schuret al Feb. 23, 1939 2,231,551 Sewall Feb. l1, 104i 2,287,341 Burns June23, 194:2 2,423,522 Samblanet July 8, 1947

